Here, ia is given by, ia=4Vx−12 ...(1) Apply KVL at node Vx , 4Vx−12+3ia+2Vx=0 Put the value of ia in above equation, 4Vx−12+3(4Vx−12)+2Vx=04Vx−12+43Vx−36+2Vx=0Vx−12+3Vx−36+2Vx=06Vx=48Vx=8V Put this value of V in equation (1) ia=48−12=−1A